Increasing which of the following would decrease the speed of a transverse wave, assuming all other variables are held constant?

A) wavelength

B) period

C) frequency

D) Planck’s constant

**Explanation**

The speed of a wave is given by the equation:

v = fλ

Since frequency and period are inverses of each other, the equation can also be expressed:

v = λ / T

Looking to these two equations, we can see that increasing the period, T, would decrease the speed of the wave, as the question asks. Thus, (B) is the correct answer.

A, C: Increasing either f or λ would increase the speed of the wave.

D: Planck’s constant is used to calculate the energy of a photon, not the speed of a wave.